Moderna announced Wednesday that it has administered the first doses of a modified vaccine designed to fight coronavirus variants to study participants.
The company said it is observing the efficacy of two different modified vaccines in a small study involving 60 people who already received the original vaccine.
Some of the participants will get a booster dose of a modified vaccine designed specifically to fight a variant of the virus first identified in South Africa. This variant has shown to reduce the immune response provoked by the original Moderna vaccine to some degree.
Other participants will get a booster dose that combines the modified vaccine with the original vaccine in order to produce a "multivalent" vaccine designed to fight multiple strains at once.
The studies are part of the company's strategy to prepare for variants of the virus if necessary.
Moderna says studies have shown its original vaccine can protect against the variants, but there is still a six-fold reduction in the level of antibodies produced against the South African strain.
Therefore, "out of an abundance of caution," the company has said it is preparing a booster dose specifically targeted against that strain if need be.
Pfizer has also been preparing for the possibility of needing booster doses.
In addition, Moderna said the National Institutes of Health will be conducting a study with its modified vaccine in participants who have not already received the original vaccine.